← Vegetable garden planting calendar

When to start seeds indoors, with a worked example

Every seed-starting date is counted from one number: your average last spring frost. Cold-hardy crops go out before it, tender ones after it, and the head start indoors is worked backwards from the day you plan to plant them out. This page works through seven crops for a garden whose average last frost is May 1.

Build your own calendar for free

The method

Pick the day the seedling goes outside (the transplant date), then subtract the weeks it needs indoors. Tomatoes go out about a week after the last frost and want six weeks inside. Peppers and eggplant go out two weeks after and want eight weeks. Broccoli and cabbage tolerate light frost, so they go out two weeks before the last frost after six weeks indoors.

Seven crops, last frost May 1

CropStart seeds indoorsTransplant outsideFirst harvest
TomatoMar 27May 8Jul 17
PepperMar 20May 15Jul 24
EggplantMar 20May 15Jul 29
BroccoliMar 6Apr 17Jun 26
CabbageMar 6Apr 17Jul 1
BasilApr 10May 15Jun 14
WatermelonApr 24May 15Aug 3

Harvest dates count from the transplant date using typical days to maturity. Basil is shown with its first cutting, not a full harvest.

Where the last frost date comes from

It is an average: in about half of years the real last frost comes after it. That is why tender seedlings wait a week or two past the date, and why the calendar has a cautious setting that adds a week more. Your local cooperative extension service or a regional frost-date table gives the average for your town.

Common questions

How do I find my last frost date?

Look up the average last spring frost and average first fall frost for your town from your local cooperative extension service, a regional frost-date table or an almanac, and enter them here. They are averages, so some years the last frost comes a week or two later. Choose the cautious setting if a late frost has caught you before.

When should I start tomato seeds indoors?

About six weeks before you plan to move the seedlings outside, and the move itself happens about a week after your average last frost. With a last frost on May 1 that means starting seeds around March 27 and transplanting around May 8. Peppers and eggplant like a longer head start of about eight weeks.

What does succession planting mean?

Sowing a small amount every couple of weeks instead of everything at once, so lettuce, radishes, beans and carrots arrive a few at a time instead of all in one week. The calendar lists each sowing date for the crops where this pays off and stops when there is no longer time to mature before frost.

Open the free planting calendar